/ Dictionary / Index P PBB: Meaning and Definition of Find definitions for: PBB Pronunciation: [key] — Chem. Chem. any of the highly toxic and possibly carcinogenic aromatic compounds consisting of two benzene rings in which bromine takes the place of two or more hydrogen atoms: used as a fire retardant and additive for plastics. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. PBA PBS Related Content Daily Word Quiz: pugilist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language